This invention relates to a stepless speed change device capable of changing its transmission speed and particularly suitable for use in a bicycle.
Such a kind of speed change device has been proposed, for example, as disclosed in Japanese Patent Application Publication No. 1,722/59.
With the prior art, however, shocks in transmission occur when the pawls taking part in transmission are switched. This results from a fact that there is a gap between tooth ends of a driving ratchet and a driven pawl which are about to take part in transmission, owing to difference in speed between them.
In the above Japanese Patent Application Publication, moreover, there are provided two stages of speed-up devices including ratchets and pawls. However, obtained speed-up ratios are often insufficient even if such two stages are used, because it is difficult for the transmission using ratchets and pawls to enlarge the speed-up ratio.